RESEARCH ARTICLE
Global and regional degree of obstruction determined by electrical impedance tomography in patients with obstructive ventilatory defect Chao Zhang1,2, Meng Dai1, Wei Liu3, Xiaohui Bai4, Jiaming Wu1,5, Canhua Xu1, Junying Xia1, Feng Fu1, Xuetao Shi1, Xiuzhen Dong1, Faguang Jin3*, Fusheng You ID1*
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1 Department of Biomedical Engineering, Fourth Military Medical University, Xi’an, Shaanxi, China, 2 Medical Engineering Section, General Hospital of Shenyang Military Region, Shenyang, Liaoning, China, 3 Department of respiratory medicine, Tangdu Hospital, Fourth Military Medical University, Xi’an, Shaanxi, China, 4 The Fifth People’s Hospital of Baoji City, Baoji, Shaanxi, China, 5 Department of Medical Technology, Bethune Military Medical NCO Academy of PLA, Shijiazhuang, Hebei, China *
[email protected] (FY);
[email protected] (FJ)
OPEN ACCESS Citation: Zhang C, Dai M, Liu W, Bai X, Wu J, Xu C, et al. (2018) Global and regional degree of obstruction determined by electrical impedance tomography in patients with obstructive ventilatory defect. PLoS ONE 13(12): e0209473. https://doi. org/10.1371/journal.pone.0209473 Editor: Y. Peter Di, University of Pittsburgh, UNITED STATES Received: February 12, 2018 Accepted: December 6, 2018 Published: December 20, 2018 Copyright: © 2018 Zhang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: Data from this study contain potentially sensitive information, thus cannot be shared publicly. Data are available from the Ethics Committee of the Fourth Military Medical University for researchers who meet the criteria for access to confidential data. Email:
[email protected] Tel: +86 029 84711415. Funding: This work was supported by the National Nature Science Foundation of China under grant 31771073, URLS: https://isisn.nsfc.gov.cn/
Abstract Background Electrical impedance tomography is a continuous imaging method capable of measuring lung volume changes. The purpose of this study was to examine whether EIT was capable of evaluating the degree of obstructive ventilatory defect (OVD) on the global and regional level.
Methods 41 healthy subjects with no lung diseases and 67 subjects suffering from obstructive lung diseases were examined using EIT and spirometry during forced vital capacity (FVC) maneuver. The subjects were divided into control group (n = 41), early airway obstruction group (n = 26), mild group (n = 17), moderate group (n = 16) and severe group (n = 8) according to the degree of obstruction. Forced expiratory volume in 1 second (FEV1) and FEV1/FVC were determined by EIT. The mode index (MI) was proposed to evaluate the degree of global and regional obstruction; the effectiveness of MI was validated by evaluating posture related change of lung emptying capacity in sitting and supine postures; the degree of regional obstruction was determined according to the cut-off values of MI obtained from receiver operating characteristic (ROC) analysis; regional obstruction was located in the four-quadrant region of interest (ROI) and the contour-map ROI with contour lines at the cut-off values of MI.
Results Significant differences were found between different groups (P
